The Mesquite Solar 2 addition is expected to be completed in late 2016, prior to the step-down of the US Investment Tax Credit (ITC) for utility projects from 30% to 10%.Southern California Edison has agreed a 20-year power purchase agreement (PPA) for the output from the expansion. The deal is awaiting approval from the California Public Utilities Commission (CPUC).

The Mesquite Solar Complex is around 60 miles west of Phoenix, Arizona.

"We are pleased to support Southern California Edison's commitment to diversify its growing renewable energy portfolio through the development of Mesquite Solar 2," said Kevin C. Sagara, president of renewables for Sempra US Gas & Power. "The expansion of our landmark Mesquite Solar complex reflects the progressive vision and leadership by the state of Arizona and Maricopa County, and we look forward to delivering a new supply of clean, emission-free energy to California consumers," he added.

Work on Mesquite 2 will begin this autumn with as many as 600 workers onsite during its peak.

The completed 1,600 hectares site will have a total capacity of 400MW, taking the company’s solar portfolio past the 1GW mark.